Method of and apparatus for molding concrete



A. VARN METHOD OF AND APPARATUS FOR MOLDING CONCRETE Filed Jan. 2, 1934 www atented Jan. 2%,

STATES METHOD oF AND APPARATUS ron Momma CONCRETE Alfredo Varni, Pallanza, Italy Application January 2, 1934, Serial No. 704,993 In Italy January 3, 1933 8 Claims.

The present invention relates to the fabrication in successive section lengths of elongated floating structures of reinforced concrete, which can be molded in a continuous process in water, for example floating piers, quays, docks and airports and the like.

It has already been suggested to build floating structures in water, particularly the hulls of ships, by pouring concrete, reinforced if desired, into floating molds, adapted to contain the structure to be formed and divided into sections which can be stripped from below after vthe molding operation is finished and which are connected to each other in a water-tight manner.

The known structures formed in this way are designed for free navigation and are therefore necessarily exposed to the rolling and pitching movements objectionable in elongated structures, which must remain practically stationary even under the swell of waves, as is required for oating quays, docks and the like.

The present invention has for its object to provide apparatus and a process for the construction in water of substantially stationary structures which can be molded in successive sections to any length, even for miles, by using a limited number of section mold assemblies of proper shape which are easy to displace along the work as the molding progresses.

In order to attain this result, several interdependent problems must first be solved, as a structure must be selected which can be molded in floating section molds of a reasonable length, which molds have to be stripped oi and carried forward or backward for fixing them to other similar section molds, not yet stripped oi or which have been placed in position.

Due notice must be taken of the fact that after the formation of the first end or intermediate section of the structure, the latter is no longer sustained by the molds but floats by itself. Hence, during its construction, the structure is generally more buoyant than the finished structure. The mold section assemblies, whether empty, partly loaded with the reinforcing trusses, or finally loaded with the poured mortar, should also float at the level of the structure undergoing construction.

The present invention seeks to obtain this result by a process of molding in sections with molds comprising oating elements, each section being capable of assembly in water-tight connection with another section or of being closed at its ends by suitable floating doors. in such a mold assembly a raft structure is molded which consists mainly of two superposed chambers, the

`upper forming an air tank and the lower being adapted for flooding with water after the structure is finished, and lateral water-tight floating tanks filled with air placed at the sides of the raft structure. The raft structure also comprises ribs, bulkheads forming water-tight compartments, and other partitions arranged and designed so as to obtain a cellular and rigid structure. 10

The m/olding may begin intermediately ff the proptseci structure and be continued from both ends of the first-molded section simultaneously by using only four floating sections of the mold, whereof the oating level should remain constant during all molding operations, commencing the work by pouring in first the two central sections and then in the two outer sections. After the completion of the four sections, the two central mold sections are dismounted and transferred to the outer ends of the two outside mold sections, whereupon after having pumped these sections dry, concrete for two further sections of the structure can be poured, one at each outer end of the existing sections, so as to form one single body with them.

During the transfer of the mold sections and the whole sequence of the work, notation will be secured by the part of the structure already molded and stripped, but not yet flooded in its lower chamber, and the floating line of the mold sec'- tions can be adjusted, according to requirements, by means provided by the invention.

In the achievement of this process, mold-section assemblies according to the present invention are used, each of which comprises a trough having its side members jointed to its bottom member by hinges, which side members are associated with flotation tanks or chambers into and from which water can be filled and emptied, 40 independently one of another. These side tanks and the trough form a fiat water-tight oating dock which can be dropped, for clearing vertically the molded structure, by iiooding the tanks on one side only of the trough, whereby this side swings downwardly about the floating tanks on the other side as pivots, the hinges permitting the trough to open. This allows the transfer of the trough to the next section of the structure to be molded where the immersed side is reoated by pumping out water from the sunken lateral tank, the companion tank on the other side being then partly lled as required to float the section in proper trim.

The downward stripping of such section molds is an easy operation, due to the natural iiexibility of their dat bottoms, particularly when their sides are made somewhat curved or pivoted to the bottoms.

In the perfomance of the invention, it is further necessary to provide for safely stripping o the oating door, which closes in water-tight manner the front end of the dock, when the next section mold is to be attached.

In such an operation the water might flood the whole dock. This must be prevented and for this purpose the present invention provides provisional end closures for the sections capable of sliding longitudinally therein and which can be applied in a Water-tight manner near the oating doors, so that the latter can be taken away without any danger of flooding during the xing of the next section mold to the free end of the dock. The water-tightness of such provisional closures can be secured in any convenient manner. Of course, the usual floating doors have to be replaced against the free front of the end section after attachment of the latter in alignment with the sections provided with provisional closures, which are slidably shifted against said floating doors only when the water contained in the added sections has been pumped out.

The progressive molding in a continuous operation of a very long structure oifers a further difculty, depending on the fact that the floating line of the molds must always exactly correspond to that of the already molded structure, both longitudinally and, especially, transversely, balancing the accidental loads on the various parts of the not yet molded dock.

Adjustment of the transverse trim is easily obtained by suitable iiooding of the system of tanks on opposite sides of the section molds, but to secure longitudinal trim adjustment at least two tanks on each side of the mold, capable of being independently lled, are necessary. To facilitate this object, the connection of a section mold to one already in position should possess a suflcient iiexibility of the resulting aggregate. The present invention provides therefore also a connecting device obtaining the above-mentioned result, allowing atany moment the checking of the conditions of the floating line and of the general balance of the iioating system.

The specification refers to the attached drawing, showing one embodiment of the invention by way of illustration:

Figures 1 and 2 show, respectively, cross and longitudinal sections of a structure according to the invention,

Figs. 3 to 5 are the two longitudinal and cross sections and a top view of the apparatus employed, and

Fig. 6 shows an operating detail.

By adopting an arrangement similar to the one shown in Fig. 1, reinforced concrete floating bodies having any length or development can be built, which are capable of carrying even very great loads, such as iloating piers or the like.

Such an arrangement comprises two hollow side bodies I-2 connected one to another by substantially horizontal walls 3-II-5, forming with the intervening spaces two chambers 6I, the upper one 6 being empty and the lower 1 lled with Water.

The two tubular bodies I---2 form the iloating part proper of the structure: chamber B should be only slightly submerged when the structure carries no extra load. This arrangement secures a good stability with regard to cross-,stresses and a capacity of supporting considerable overloads.

IIhe position of wall 4 should be designed properly according to requirements.

In order to prevent any eventual port-hole in the walls of the iloating bodies from endangering the stability Vof the structure and to. attain the greatest strength of the whole, it is desirable to design the oating bodies with a cellular structure with transverse walls 8, substantially vertical and suitably spaced along the structure" (Fig. 2).

The structure can" be reinforced also by ribs 9-I II, by connecting walls I I, by struts I8, and by tension rods and other members not shown and familiar to those skilled in the art.

The resulting structure forms a continuous beam, continuously supported, so that each of its elements has great rigidity, but the whole is very elastic when a sutlicient length of it is taken into consideration. Its actual construction is very easy and can be carried out even in water with the device shown in Figs. 3 to 5.

This device is formed of a number of section molds I2, end-connected so as to dene a trough open on its upper side. To the free ends of any two such sections are applied floatingwalls I3 or doors applied by simple hydrostatic pressure. closing the trough and allowing any water contained in the molds to be evacuated by any convenient means.

To both sides of each section mold are iixed the iiotation tanks It, preferably two on one side and two on the other side, as shown in the drawing. Such tanks are water-tight and can be flooded more or less with Water so as to achieve the desired floating conditions at the various phases of construction. When these tanks are four in number, two for each side, they will allow the trim of the mold trough to be varied both lengthwise and transversely.

The connection between the bottom I2" and the two side walls I2' of the trough must be such as to allow the section molds to disengage downwards from the parts of the structure already cast and solidified', either due to an upward inclination of said walls or to a sufcient elasticity of the whole system of molds. In the embodiment shown, the side walls I2 of said molds are connected to the bottom I2 by hinges I2': the reciprocal surfaces of contact are, however, arranged so as to secure water-tightness when the side walls are lifted. At the top, said side walls can be connected together by demountable transoms or tension bars I5 of any known kind. In the inside of these troughs, open at the top, are arranged in known manner the vertical and horizontal forms necessary to form the intermediate or dividing walls, of the strengthening ribs and the like.

The front edges of each of the mold elements are provided with a suiliciently thick and wide dressing of rubber to secure a good water-tightness at the joint even when the latter is eiected by bolted flanges I 6. These joints should be tightened fully in connecting sections in which the concrete is being poured. Other joints may ea-somewhat less tight, so that the rubber is squeezed only enough to guarantee water-tightness.

In these conditions it is possible to check, in the sections where the operations of molding have not yet begun, whether or not the floating (water-line) is correct, or if there are any uplifting forces which can endanger either the pouring operation or the strength of the mold.

This check can be easily made with flexometers. sures capable of sealing the end of the trough near The pouring can begin conveniently from the center of the structure, so as to have two working fronts proceeding in opposite directions. When this center part of the structure is nished, the center section mold or molds can be transieri-ed to the two ends of outer section molds, proceeding in like manner to completion of said structure.

The operation is rendered very easy, dueto the possibility of ballasting and unballasting the lateral tanks it and tothe hinges between the side walls l2 and the bottom I2" of each section mold l2. In fact, the ballasting of tanks Il' sinks the mold, as shown in Fig. 4, the system remaining suspended to the oating tanks Il" which are correspondingly unballasted. When the end floating doors I3 have to be taken away, the provisional closures I3' are handled in the following mannerz- In each mold the concrete is poured progressively towards the end which is sealed by the oating door I3. Before the pour--v ing has reached this point the provisional door is removed allowing the water to enter the small space between the end and the provisional door. Another mold section is attached, which has been transferred from an already finished section of the structure, and the floating door is applied to the far end of the transferred mold section. The water occupying this section and the said small space is then removed, and the provisional door is slid along inside the new section to a position near the oating door, enabling the next section of the work to proceed. The caulking of the provisional doors can be achieved by using rubber pipes lodged in a circular groove cut in the edge of said closures, air being pumped into the pipes when in position.

When the molding is completed, the central lower chamber of the structure is suitably flooded so as to obtain the conditions of notation and immersion required for service. Thus the central part of the structure already molded and solidiiied can be stripped progressively of the section molds which will be subsequently transferred to both ends in the course of construction.

Oi course, the structure may be provided with manholes il for inspection and for scavenging operationsVas also with all the complementary structures required according to the service to be done by the construction.

I claim as my invention:-

l. Apparatus for molding in successive section lengths long iioating concrete structure, comprising a trough mold section adapted to be readily disengaged in a downward direction from the structure molded therein, a plurality of otation chambers extending along the outside of each side member of the trough section, means for ooding and emptying said chambers individually, and working closures for the ends of the trough, and provisional closures capable of sealing the end of the trough near the Working closure to enable the latter to be removed and of being slid longitudinally of the trough before concrete is poured in the latter.

2. Apparatus for molding in successive section lengths long iioating concrete structures, comprising a trough mold section, hinge connections between the bottom and two side members of the trough mold section, a plurality of flotation charnbers extending along the outside of each side member of the trough section, oating doors attachable to the ends of the trough to forn watertight closures for the same, and provisional clothe working closure to enable the latter to be removed and of being slid longitudinally of the trough before concrete is poured in the latter.

3. Apparatus for molding in successive section 5 lengths long oating concrete structures, comprising a trough mold section, hingeconnections between the bottom and two side members of the trough mold section, a plurality of notation chambers extending along the outside of each side member of the trough section, means for ilooding and emptying said chambers individually, working closures for the ends of the trough, and provisional closures capable o! sealing the end or the trough near the working closure to enable the latter to be removed and o! being slid longitudinally of the trough before concrete is poured in the latter and means for connecting the trough section mold to a similar section mold, saidmeans including flexible gaskets forming yielding joints between the said section molds.

4. A process for molding in water oating monolithic concrete structures, comprising assembling and oating in water a plurality of mold sections and flotation chambers to form a trough o5 in the line of the structure to be formed and including inner and outer mold sections considered longitudinally of the structure, sealing the free ends of the trough by means of working closures, removing water from the trough, mounting in the trough framing for molding the walls and partitions of a length of the structure, casting concrete in the trough, allowing the concrete to set, disconnecting inner mold sections from outer mold sections and removing the former downwardly from the structure, substituting provisional for the working closures at the ends of the trough, attaching the removed mold sections to th outer ends ,of the outer section to form an extension of the trough in the direction of construction, and repeating the procedure to add further lengths to the structure.

5. A process for molding in water floating monolithic concrete structures, comprising assembling and iioating in water a plurality of mold sections andotation chambers to form a trough in the line of thqstructure to be formed and including inner and outer mold sections considered longitudinally of the structure, sealing the -free ends of the trough by means of working closures, removing water from the trough, mounting in the trough framing for molding the walls and partitions of a length of the structure, casting concrete in the trough, allowing the concrete to set, disconnecting inner mold sections from outer mold sections and removing the former downwardly from the structure, substituting provisional for the working closures at the ends of the trough, attaching the removed mold sections to the outer ends of the outer section to form an extension of the trough in the direction of construction, and repeating the procedure to add further lengths to the structure, the framing beingso arranged in the trough sections as to form a cellular concrete structure having in cross-sec- 55 tion two side notation chambers and two central superposed chambers of which the lower can be ooded.

6. A process for molding in water iioating monolithic concrete structures, comprising assembling and noating in water a plurality of mold sections and flotation chambers to form a trough in the line of the structure to be formed and including inner and outer mold sections considered longitudinally of the structure, sealing the free ends of the trough by means of iloating doors, renioving water from the trough, mounting in the trough framing for molding the walls and partitions of a length of the structure, casting concrete in thel trough, all wing the concrete to set, disconnecting inner mo d sections from out-er mold sections and removing the former downwardly from the structure, substituting provisional closures for the iioating doors, attaching the removed trough sections of the outer ends of the outer section to form an extension of the trough in the direction of construction, and repeating the procedure to form further lengths or' the structure.

7. A process, for mol-ding in water floating monolithic concrete structures, comprising,r assembling and iloating in water a plurality of mold sections and notation chambers to form a trough in the line of the structure to be formed and including inner and outer mold sections considered longitudinally of the structure, sealing the free ends of the trough by means of floating doors, removing water from the trough, mounting in the trough framing for molding the walls and partitions of a length of the structure, casting concrete in the trough, allowing the concrete to set, disconnecting inner mold sections from outer mold sections and removing the former downwardly from the structure by admitting water to flotation chambers on one side oithe mold section and permitting the 'whole section to swing transversely to the structure about the opposite flotation chambers as pivot, substituting provisional closures for the working doors, bringing the removed mold section to the outer end of an outer mold section and into position to form an extension of its trough section by removing water from the oo-:ied chambers, and repeating the procedure to form further lengths of the strucure.

8. A process for molding in water iloatlng monolithic concrete structures according to claim 4, including the step of adjusting misalignment of adjoining trough sections by interposing connections ncluding flexible gaskets at the joints between said sections.

ALFREDO VARNI. 

